Well i'm running a rear avid ultimate with XTR lever a ceramic d521 heatsink pads and a odeysey liner slic cable. The brake is pretty rad and locks really well but it has no bite what so ever, I'm getting rid my ceramic rim now and getting a ronnie and having a grind as the ceramic gives no bite, i've tried every thing to make it bite better. You could try cleaning you rim, I use white spirits then i wash it down with hot water. Are your pads hitting the rim dead on and straight and are they hitting the rim at the same time, Just tweak at it i spent like 3 hours on my rear v set up and i got it so sweet. I'm sure paul oliver will be in this thread soon, He will sort you out as he bums v brakes don't you paul . Ben